Electrical stimulation of peripheral and central neural structures has shown increased interest due to the potential benefits it may provide to individuals suffering from many neurological and behavioral diseases. Many of these therapies today are not well accepted due to the invasive nature of the therapy, even though the efficacy is quite good. This has created a need for less invasive therapies that are directed toward patient and physician clinical needs.
Headaches are one of the most debilitating ailments that afflict millions of individuals worldwide. The specific pathophysiology of headaches is unknown. Known sources of headache pain consist of trauma, vascular, autoimmune, degenerative, infectious, drug and medication-induced, inflammatory, neoplastic, metabolic-endocrine, iatrogenic, musculoskeletal and myofacial causes. Also, even though the possible underlying cause of the headache pain is identified and treated, the headache pain may persist.
Currently, the sphenopalatine (pterygopalatine) ganglion (SPG) is a target of manipulation in clinical medicine to treat headaches. The SPG is an extracranial neuronal center located behind the nose. It consists of parasympathetic neurons that innervate (in part) the middle cerebral and anterior cerebral blood vessels, the facial blood vessels, and the lacrimal glands. The SPG also consists of sympathetic and sensory nerve fibers that pass through the SPG in route to their end organs. Manipulation of the SPG is mostly performed in attempted treatments of severe headaches, such as cluster headaches or chronic migraines.
Various clinical approaches have been used for over 100 years to modulate the function of the SPG to treat headaches. These procedures vary from least invasive (e.g. transnasal anesthetic blocks) to much more invasive (e.g. surgical ganglionectomy) as well as procedures such as surgical anesthetic injections, ablations, gamma knife and cryogenic surgery. Most of these procedures have very good short term efficacy outcomes (days to months), however these results are usually temporary and the headache pain returns. A chronically implanted SPG neurostimulator may provide much better long term efficacy in these patients.